Don’t capitalize astronaut.
Change 2 to two. (That sentence must look really scary to people who rely on phonetics alone, rather than context and whatnot, to tell them how to spell a word. *wicked-yet-also-exasperated editor grin*)
An astronaut can be up to two inches taller after spending time in space. The cartilage discs in the spine expand in the absence of gravity.
For anyone who cannot manage significant time in free-fall for un-compressing their spine, I recommend an inversion table; it allows you to use gravity to undo some of what gravity did to your body in the first place. Plus, you can keep one in your home, unlike a space shuttle/station, there’s no increased exposure to radiation while using one, and — this is very important — tall people can use inversion tables, but they can’t become astronauts.